a)50 + x = 180 - 120

 50 + x = 60

 x = 60-50 

 x = 10

b)20-x = 150-140

 20-x = 10

x = 20-10

x = 10

c) 25+x = 100-40

25+x=60

x= 60-25

x=35

d) 100+x =130-25

100+x = 105

x = 105-100

x = 5

e) 143+x = 174-22

143+x = 152

x = 152-143

x = 9 

ỦNG HỘ MK NHÁ

120 + ( 50 + x ) = 180

50 + x = 180 - 120

50 + x = 60

x = 60 - 50

x = 10

140 + ( 20 - x ) = 150

20 - x = 150 - 140

20 - x = 10

x = 20 - 10

x = 10

100 - ( 25 + x ) = 40

25 + x = 100 - 40

25 + x = 60

x = 60 - 25

x = 35

130 - ( 100 + x ) = 25

100 + x = 130 - 25

100 + x = 105

x = 105 - 100

x = 5

174 - ( 143 + x ) = 22

143 + x = 174 - 22

143 + x = 152

x = 152 - 143

x = 9

k mk nha 

Thanks nhìu

\(120+\left(50+x\right)=180\)

\(\Rightarrow50+x=180-120\)

\(\Rightarrow50+x=60\)

\(\Rightarrow x=60-50=10\)

Vậy x = 10

\(140+\left(20-x\right)=150\)

\(\Rightarrow20-x=150-140\)

\(\Rightarrow20-x=10\)

\(\Rightarrow x=20-10=10\)

Vậy x =x10

\(100-\left(25+x\right)=40\)

\(\Rightarrow25+x=100-40\)

\(\Rightarrow25+x=60\)

\(\Rightarrow x=60-25=35\)

Vậy x = 35

\(130-\left(100+x\right)=25\)

\(\Rightarrow100+x=130-25\)

\(\Rightarrow100+x=105\)

\(\Rightarrow x=105-100=5\)

Vậy x = 5

\(174-\left(143+x\right)=22\)

\(\Rightarrow143+x=174-22\)

\(\Rightarrow143+x=152\)

\(\Rightarrow x=152-143=9\)

Vậy x = 9

a. 580:(x-24)=329-150.2

    580:(x-24)=329-300

    580:(x-24)=29

            x-24=580:29

            x-24=20

                x=20+24

                x=44

b.43-(24-x)=20

         24-x= 43-20

         24-x=23

              x=24-23

              x=1

c.5.(x-30)+25=100

   5.(x-30)      =100-25

   5.(x-30)      =75 

       x-30        =75:5 

       x-30        =15

           x         =15+30 

           x         =45

e.x-140:35=270

   x-4=270

       x=270+4

       x=274

Câu d hình như đề bài sai rồi bạn

100: x = 140 -120 => 100: x = 20 => x = 100:20 => x = 5

140 - 100 : x = 120 

100 : x = 140 - 120

100 : x = 20

x = 100 : 20 

x = 5

\(140-100:x=120\)

\(100:x=140-120\)

\(100:x=20\)

\(x=100:20\)

\(x=5\)

140 - 100 : x = 120

         100 : x = 140 - 120

         100 : x = 20

                 x = 100 : 20 

                 x = 5

\(\left(x-20\right):\left(x-10\right)=\left(x+140\right):\left(x+70\right)\text{ hay }\frac{x-20}{x-10}=\frac{x+140}{x+70}\)

\(\text{Áp dụng tính chất của dãy tỉ số bằng nhau ta có:}\)

\(\frac{x-20}{x-10}=\frac{x+140}{x+70}=\frac{x-20-\left(x+140\right)}{x-10-\left(x+70\right)}=\frac{x-20-x-140}{x-10-x-70}=\frac{-160}{-80}=2\)

\(\text{Suy ra:}\frac{x-20}{x-10}=2\Rightarrow x-20=2.\left(x-10\right)\)

\(x-20=2x-20\)

\(x-2x=-20+20\)

\(-x=0\)

\(x=0\)

x=0              

x=10

15 ( x - 1 ) + 20 ( x - 1 ) = 140

=> ( x - 1 ) ( 15 + 20 ) = 140

=> ( x - 1 ) . 35 = 140

=> x - 1 = 4

=> x = 5

giải luôn nhé:

(x-1)(15+20)=140

(x-1)35=140

x-1=140-35

x-1=105

x=105+1

x=105

Vậy x=106

x=106 nhé, mik ghi nhầm bn ạ

Vì 112 ⋮ x ; 140 ⋮ x nên x ∈ ƯC(112, 140).

Ta có 112 = 24.7 ; 140 = 22.5.7

⇒ ƯCLN(112, 140) = 22.7 = 28.

⇒ ƯC(112, 140) = Ư(28) = {1, 2, 4, 7, 14, 28}.

⇒ x ∈ {1; 2; 4; 7; 14; 28}.

Mà 10 < x < 20 nên x = 14.

Ta có: \(112⋮x\)

\(140⋮x\)

Do đó: \(x\inƯC\left(112;140\right)\)

\(\Leftrightarrow x\in\left\{1;2;4;7;14;28\right\}\)

mà 10<x<20

nên x=14